Unicellular algae represent a potentially inexpensive, scalable, CO2-fixing, phototrophic source of biopharmaceuticals, vaccines, antibodies, biofuels, food additives, cosmetics, animal feed additives, pigments, polysaccharides, fatty acids, biomass, and a wide array of various other chemical products. The ability of algae to act as bioreactors for the production of the above-listed substances, has led to considerable efforts to understand the complexities of these microscopic organisms, and to be able to engineer them for a variety of uses.
Algae also have value as feedstocks, for example, for aquaculture. Microalgae feeds for aquaculture (“aquafeeds”) are currently produced in small amounts by hundreds of aquaculture operations and some commercial producers. These supply microalgae feeds, for use by bivalve, fish, shrimp and other aquaculture markets. However, costs are high (>$100/kg of dry biomass), production systems small, and global production of such microalgae aquaculture feeds is at most a few hundred tons a year. Low costs are achievable through strain selection and higher productivity by increasing the scale of production from a few hectares and small ponds to several hundred hectares with much larger growth ponds. Additionally, a very large market for aquaculture feeds could be developed for microalgae biomass containing long chain omega-3 fatty acids, to replace fishmeal and oil, but for this production costs must be reduced. Achieving such a low costs will require more efficient production systems, as well as improved strains.
Various methods have been attempted to engineer and transform a number algal strains. For example, current methods include micro-projectile bombardment, particle gun transformation, gene gun transformation, or simply bioballistics. These methods often makes use of DNA-coated heavy-metal (mostly gold) micro-projectiles and allow transformation of almost any type of cell, regardless of the thickness or rigidity of the cell wall, and also allow transformation of organelles. Additional examples of methods are lipid carrier transformation protocols, electroporation, parental mating, and viral based transformation for example with Agrobacterium.
Unfortunately, in many cases the existing methodologies suffer from poor efficiency, have narrow or limited applicability among different types of algae, result in transformants with poor stability, and/or cause harm to many of the targeted algae. Embodiments described herein generally relate to new and improved methods for the introducing exogenous substances into wide variety of algae, for example, with greater efficiency and success, and wider applicability to a variety of algae.